Axial Velocity Profiles Research Articles

Numerical simulations of high Prandtl number liquid jets impinging on a flat plate

In this work, 3D simulations of oil jets impinging on a flat, heated wall are presented. The numerical setup uses the Volume of Fluid (VoF) method to model the two-phase flow. A careful grid definition across the liquid film, along with the use of the Conjugate Heat Transfer (CHT) approach allowed local heat transfer to be solved with fine resolution at the wall. Variations of liquid flow rate, liquid temperature and surface temperature allow to cover a wide range of local Reynolds and Prandtl numbers (226<Re<2850, 77<Pr<161). Resulting surface-averaged heat transfer compares very well with experimental measurements conducted in a previous study. In-depth analysis of the flow has identified expected features from the literature. In particular, the impact of jet axial velocity profiles on the heat transfer distribution in the stagnation zone was clearly stated. The increase in heat transfer when warming the liquid film was also reproduced and explained by a decrease in oil viscosity and an increase in film velocity. All those effects were taken into account in correlations for stagnation and local values of Nusselt number. A grid sensitivity study was also conducted, showing that if the grid solving the thermal boundary layer in the stagnation zone can be coarsened without impacting local and surface-averaged predictions of heat transfer, a minimum resolution (2 to 3 cells) within the thermal boundary layer is however required for an accurate prediction of heat transfer.

Simulating and interpretation of MHD peristaltic transport of dissipated Eyring–Powell nanofluid flow through vertical divergent/nondivergent channel

The primary goal of this study is to present a novel suggestion to uncover the characteristic features of the peristaltic flow of Eyring–Powell nanofluid through divergent and nondivergent channels. Several strategies are used to enhance the heat transfer capacity. Heat transport can be improved by increasing the thermal conductivity of the materials using nanoparticles. The implementation of a low Reynolds number and large wavelength hypothesis brings to reduce the system’s complexity. The resulting nonlinear coupled differential equation system is solved numerically by utilizing Mathematica symbolical software (ND-Solve). Various configurations of the outer boundaries are considered, namely, square wave, multi-sinusoidal wave, trapezoidal wave, and triangular wave. Under the effect of pertinent flow parameters, graphical illustrations of axial velocity, thermal, and concentration profiles have been portrayed. In tabular form, numerical outcomes for the rate of heat as well as mass transfers are displayed. One of the most significant phenomena concerning peristaltic motion, known as the trapping phenomenon, has also been spotlighted using contour plots and circulating bolus. The major outcomes revealed that the square wave shape gives higher pressure gradients near the inlet and outlet parts while the multi-sinusoidal wave gives periodic behaviors of It is noteworthy that Eyring–Powell fluid characteristics display a tendency to diminish the thermal resistance and axial velocity near the walls for divergent channels while an enhancement in velocity is observed at the region as Eyring–Powell fluid parameter is altered. Further, for various kinds of divergent channels, the rate of heat transmission is enhanced due to an augmentation in Eyring–Powell fluid characteristics. Also, the present study uncovers that the parameters of the magnetic field and the Eyring–Powell fluid materials have a significant influence on the trapping phenomenon for both types of channels.

Significance of radiant-energy and multiple slips on magnetohydrodynamic flow of single-walled carbon nanotube-water, titanium dioxide–water, multiwalled carbon nanotube–water, graphene oxide–water nanofluids

The magnetohydrodynamic flow of nanofluid is studied in the present analysis by using two parallel, rotating, and stretchable disks with a porous medium. The thermal radiation effects along with velocity slips at the interface of fluid and disk are considered in this work. The water is taken as base fluid, and carbon nanotubes (CNTs), titanium dioxide (TiO[Formula: see text]), and graphene oxide (GO) are taken as nanoparticles. The corresponding equations are modeled in terms of partial differential equations and Von Karman similarity transformation approach is adopted. The resulting equations are solved by using a finite difference method-based ND Solver. The axial, radial, and tangential velocity profiles and temperature distribution are discussed with graphs and tables. Thermal radiation and convective boundary conditions are used in the heat transfer process. When the thermal Biot number of the lower disk rises, fluid temperature enhances, whereas, the fluid temperature falls with the rise in the thermal Biot number of the lower disk. It is observed that when the thermal Biot number of lower disk rises from 0.5 to 0.8, heat transfer at lower disk is increased by about 6.66% in hexagonal-shaped CNTs-based nanofluid and 6.66% in spherical shaped TiO[Formula: see text] and GO-based nanofluid. The impact of physical parameters such as skin friction coefficient and Nusselt number are computed for governing parameters and discussed in detail.

Numerical investigations of pipe flow downstream a flow conditioner with bundle of tubes

Flow conditioners are widely utilized in pipeline systems to improve the precision of flow rate measurement in the pipeline systems of the offshore and subsea oil and gas industry. There is a lack of knowledge about the influences of the conditioners on the flow inside a bend pipe due to the measurement inaccuracy caused by geometries complexity. In this study, numerical simulations are carried out solving the three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations with the κ–ω SST model to investigate the large-scale flow characteristics inside a double bend pipe and the performance of a conditioner with a bundle of 19 tubes. The obtained axial velocity inside a double bend pipe flow with no flow conditioner are compared with those of the previously published numerical simulations results and experimental data as the validation study. Helical flow structures are found behind the double bend and effectively removed by the flow conditioner. The performance of the flow conditioner is evaluated based on the axial flow velocity profiles, the swirl intensities and the deviation from the flow inside a straight pipe. The effects of Reynolds numbers and the lengths of the tube bundle on the flow downstream the flow conditioner are discussed.

MODELING LAMINAR FLOW IN CONVERGING-DIVERGING CHANNELS

Converging-diverging channels have been known to have low net charge (flow parameters) due to associated high frictional flow resistance. Thus, there is a need to optimize frictional flow resistance in these channels. To this end, frictional flow resistance was optimized for a laminar, fully formed flow in a linearly varying cross-sectional converging-diverging channel in this study. To achieve this, an empirical frictional flow resistance model was developed using continuity and momentum equations, and this accurately represents a parabolic axial velocity profile in converging-diverging section. The developed model was solved and parametric investigations carried out on geometrical and fluid flow parameters using MATLAB 6.1. The results show that the frictional flow resistance decreases as radius ratios increases, but increases as Reynolds number and taper angle increase. Radius ratios and Reynolds numbers were found to be more significant than taper angles. Results in comparison to available literature showed that the developed frictional flow model is an accurate model as it predicts axial velocity and the flow resistance with a high degree of precision. The study concludes that, for frictional flow resistance to be kept at barest minimum in a converging diverging channel, radius ratio must be maintained at its highest value and Reynolds number at its lowest possible value.

Cooling of Steam Turbine Exhaust Hood and Last Stage Blade

This paper describes a novel semi-numerical method of water droplets path lines calculation in steam turbine axial exhaust hood 2D space. The axial velocity profile of steam as well as droplets evaporation are taken into account. Water droplets occur in several cooling nozzles placed on the outer wall of axial exhaust hood. Mathematical model of all water nozzles used in Doosan Škoda steam turbines was developed. Position and angle of cooling nozzles towards the outer exhaust hood wall influence the possibility of last stage blade trailing edges erosion given by droplets flow from the nozzles. The turbine lifetime is prolonged as the final consequence.

Study of Steam-Induced Convection in a Rotating Vertical Flow Channel

The phenomenon of steam–water direct contact condensation has significance in a wide range of industrial applications. Superheated steam was injected upward into a cylindrical water vessel. Visual observations were conducted on a turbulent steam jet to determine the dimensionless steam jet length compared to the steam nozzle exit diameter and the steam maximum swelling ratio as a function of steam mass flux at the nozzle exit, with a gas steam flux ranging from 295–883 kg/m2s. The Reynolds number based on the steam jet’s maximum expansion ranged from 41,000 to 93,000. Farther above of the condensation region, the jet evolved as a single-phase heated plume, surrounded by ambient water. Mean axial central velocity profiles were determined against the steam mass flux ranging from 295–883 kg/m2s to observe the exponential drop in the mean axial velocity as the vertical distance increased. The radial velocity distribution within the spread of the jet was determined to be self-similar, and the radial distribution of the velocity profile followed the Gaussian function, after the proper scaling of the vertical distance and the axial mean velocity.

Rotation, electromagnetic field, and variable thermal conductivity effects on free convection flow past an eternity vertical porous plate

AbstractThe present research may facilitate the reduction of the number of conversion steps required to include the low output voltages in an electrokinetic biomass process. Variable thermal conductivity and electroosmosis flow have already established great potential in the thermo‐elastic models of various manufacturing industries and have been widely used in energy technologies. As a result, the current framework investigates the characteristics of natural convection flow with the influence of variable thermal conductivity and electroosmosis over an eternity vertical porous plate. Coriolis forces and Hall current effects are considered in the momentum equations, and also thermal radiation and variable thermal conductivity are taken as energy equations. A linear chemical reaction parameter is used in the concentration equation. The equation of Poisson–Boltzmann is exploited to depict the electric potential characteristics within the accelerated plate medium. The pdepe command in Matlab software is used to figure out the numerical solutions to equations about momentum, energy, and concentration. The expressions of fluid transverse velocity, fluid axial velocity, fluid temperature, and concentration profiles are presented as numerical results and also derived vital relevant stream parameters diagrammatically, whereas the numerical values of primary skin friction, secondary skin friction, and Nusselt number are presented in tabular form for various values of pertinent flow parameters. The temperature rises as the strength of the thermal conductivity variable parameter increases. Also, as the values of the Taylor number and the thermal conductivity variable parameter go up, the primary velocity goes down. Similarly, secondary velocity increases in the opposite direction as the Taylor number and thermal conductivity variable parameter increase.

Flow and Heat Transfer Analysis MHD Nanofluid due to Convective Stretching Sheet

Objectives: The study of flow and heat transfer on a permeable stretching sheet of Magnetohydrodynamic nanofluid under the influence of convective boundary condition is presented in this article. Mathematical modeling for the law of conservation of mass, momentum, heat and concentration of nanoparticles is executed. Methods: Governing nonlinear partial differential equations are reduced into nonlinear ordinary differential equations and then shooting method with fourth order Adams-Moulton Method is employed for its solution. Findings: The effects of magnetic parameter (0  M  2), Thermophoresis parameter (0:1  Nt  0:7) Lewis number (1  Le  4), Suction parameter (0  fw  3), Biot number(0:1  Bi  0:7) and Viscous dissipation(0  Ec  4) on axial velocity, temperature and concentration profiles are shown graphically. Numerical results were compared with another numerical approach and an excellent agreement was observed. The solutions under the impacts of different physical governing parameters are illustrated by means of graphs and tables. Effects of viscous dissipation is also discussed. Novelty: Despite the enormous importance and repeated application of nanofluids in industry and science, no attempt has been made to investigate the viscous dissipation effect on heat transfer with a permeable linear stretch sheet. Keywords: MHD; Nanofluid; Stretching Sheet; Viscous dissipation; Shooting technique; Adams-Moulton Method

Gas-dynamic losses in the flow part of the channel charge of a solid-propellant rocket engine

Modern methods of computational fluid dynamics have been used to study flows with mass supply in axisymmetric channels of solid-propellant rocket motor charges. The studies were carried out with the aim of increasing the accuracy of predicting the intraballistic parameters for performing engineering calculations. The analysis of changes in intraballistic characteristics in the flow part of the channel charge in the classical and nozzleless solid propellant rocket motors is carried out for different rates of mass supply from the combustion surface. For an isobaric combustion chamber, a characteristic velocity profile is shown along a tubular charge path and a charge with sudden expansion. It is shown that for a steady cosine profile of axial velocity after sudden expansion of the channel, a length of more than three gauges is required. For a high-speed combustion chamber, a comparison of the axial velocity profile is carried out depending on the flow velocity under different conditions of mass supply. The tendency of the influence of flow velocity on the character of the profile is noted. It is shown that at a Mach number over 0.5, an increase in the mass flow rate from the combustion surface provides a less filled velocity profile tending to cosine. The differences between the pressure losses in the flow passage of the channel charge, calculated in the axisymmetric approximation, and the losses determined using gas-dynamic functions, are shown. An increase of the mass flow rate in the charge channel of a nozzleless solid-propellant rocket motor leads to a decrease in pressure losses at Mach number over 0.8.

Effects of curvature existence, adding of nanoparticles and changing the circular minichannel shape on behavior of two-phase laminar mixed convection of Ag/water nanofluid

In the present research, heat transfer behavior and Ag/water two-phase laminar nanofluid flow as cooling fluid in volume fraction of nanoparticles 0–6 % and Reynolds numbers of 200–500 in a tube with curvature angle of 270° are simulated utilizing finite volume method. 3-D simulations of laminar mixed convection two-phase nanofluid flow considering Grashof numbers of 5,000, 50,000 and 100,000 are carried out numerically. The results of the present research indicate that adding solid nanoparticles causes periodic behavior with particular repeat length on the axial velocity profile and maximum and minimum values shift every 60°. Also, after the curvature angle of 30° because of fluid motion, centrifugal forces importance, fluid rotation, and hydrodynamic field, local friction factor increases considerably up to channel outlet. In all diagrams, the maximum friction factor is related to the Grashof number of 100,000, this value will have more significant augmentation by the increase of volume fraction. Due to better fluid mixing and increase of temperature line slop at Reynolds number of 500, heat transfer enhances at the regions of the bottom bend of the channel. Higher volume fractions of nanoparticles reinforce the heat transfer mechanism and heat absorption from the hot surface. In the regions where fluid is influenced by thermal boundary layer growth, entropy generation is augmented. This entropy generation is due to heat transfer. On the other hand, entropy generation is reduced in the regions where the effect of inlet fluid temperature is dominated.

Formation and breakup of twisting ligaments in a viscous swirling liquid jet

We analyze the successive steps of the breakup morphology of a swirling liquid jet. Three-dimensional numerical simulations are carried out using the Volume of Fluid method with adaptive mesh refinement for axial Reynolds numbers of 50 and swirl numbers of 0.50≤S≤1.55. We present fundamental flow features of the swirling jet in terms of time-averaged axial and azimuthal velocity profiles for the considered range of swirl numbers. The provision of a swirl induces helical disturbance at the interface of the jet, which exhibits an azimuthal mode number of m = 4. We identified that viscous forces are the most dominant force in the flow, which causes the suppression of Kelvin–Helmholtz instability at the interface. In contrast, we found the existence of centrifugal instability, which destabilizes the helical rim developing at the interface. As a result, centrifugally induced corrugations in the form of tiny protrusions develop along each of the helical rims, which triggers Rayleigh–Taylor instability. Subsequently, these tiny protrusions get stretched in the radially outward direction and transform into twisting ligaments that break into droplets. We have elucidated the mechanism for the twisting of ligaments and its further disintegration into first-generation droplets, which has not been reported in previous studies.

Studies on flow field, and instabilities in a large diameter opposed jet burner

This work reports studies on flow fields, and instabilities exhibited by opposed jets at equal momenta, for Reynolds numbers (Re) ranging from 178 to 5000 using a large diameter counterflow jet setup. Flow instability investigations were conducted over a range of aspect ratios (α) too. This study identifies the regions of bi-stability and those of oscillatory stagnation plane offsets identified by Re. Experiments on flow field were carried out using particle image velocimetry technique, and the paper presents the axial and radial velocity profiles at various locations as well as their gradients. A decreasing trend in stagnation plane displacements with the Reynolds number was observed. The experiments in comparison with the past literature suggest a possible dependence of the stagnation plane displacements on a nozzle-exit diameter. The trends in maximum stagnation plane displacements (δmax), as well as the critical Reynolds numbers (Recr) with aspect ratios (α), are analyzed and compared. The flow field studies reveal the need for two dimensional axisymmetric simulations with realistic velocity boundary conditions to predict opposed jet flow phenomena accurately. Reacting flow instability studies were also carried out for equal momenta using methane-air and ethylene–air flames at various aspect ratios. The results show an enhanced bistability for ethylene–air flames over methane–air flames.

Numerical study of satellite droplet formation in dripping faucet

• Dynamic relation between the liquid/gas interface, pressure and velocity profile has been investigated. • Physics of capillary wave generation in liquid filament has been analyzed. • Satellite drop generation depends on the acceleration and distribution of the axial velocity at the cone-filament junction. • Satellite drop is less likely to be formed at high inlet velocity and low surface tension coefficient. Dynamics of primary and satellite drop formation has wide engineering applications. Drop formation from a vertical capillary tube in air goes through various stages that include necking, bifurcation, recoil, wave generation and secondary necking and bifurcation. In this study, the problem has been studied numerically where the free surface of the pendant drop is tracked by a coupled level set and volume-of-fluid method with the surface tension force determined by the continuum surface force model. The evolution of the complete droplet separation process has been simulated. The numerical results have been compared with published experimental data. The mechanism for the recoiling of the liquid filament after droplet detachment and the subsequent formation of a satellite droplet has been studied and dynamic correlation among liquid/gas interface topology, velocity and pressure field has been investigated. Bell shaped distribution of axial velocity profile and fast acceleration at the cone-filament junction has been found to lead to satellite drop generation. Parametric studies on the effects of inlet velocity, surface tension coefficient and viscosity have been performed. Satellite droplet is less likely to be formed at high inlet velocity and low surface tension coefficient. Viscosity, on the other hand, has been found to play an important role on the shape of liquid filament and satellite droplet. These findings can help better understanding of drop-on-demand liquid dispensing, inkjet printing, spray combustion and many more engineering applications.

Convective thermal conditions and the thermophoretic effect's impacts on a hybrid nanofluid over a moving thin needle

AbstractThis research focuses on the heat source/sink, chemical reaction, and thermophoretic particle deposition in the influence of hybrid nanofluid over a moving thin needle subjected to a magnetic field. Using the appropriate transformations, a group of nonlinear partial differential equations may be converted to ordinary differential equations. Additionally, with the aid of computational software, the RKF‐45 approach is used for the numerical assessment, as well as the shooting operation. It should be mentioned that the results' approval demonstrates a strong association with the previous findings. The resulting graphs mainly explain the fundamental characteristics of hybrid nanofluids and nanofluids, as well as the consequences of different restrictions. An increase in needle size enhances the velocity profile, temperature profile, and concentration profile. The radial and axial velocity profiles are reduced when the magnetic constraint is increased, whereas the thermal and concentration patterns are reversed. Improved heat source‐sink as well as Biot number values will enhance the thermal profile. The concentration profiles will decrease due to reaction rate restrictions and thermophoretic limits. The inclusion of solid volume fraction reduces surface drag forces while increasing the rate of mass transfer. In most circumstances, hybrid nanofluid plays a prominent role than nanofluid.

Irreversibility analysis on the radiative buoyancy flow toward stagnation point through water conveying three kinds of nanoparticles past a heated vertical flat plate with the ramification of Hall effects

Recent advancements in nanotechnology have created a tremendous platform for the development of the improved performance of ultrahigh coolants known as nanofluids for several industrial and engineering technologies. The present research peruses an inspection of irreversibility analysis of mixed convective flow near a stagnation point provoked by ternary hybrid nanoparticles through a vertical heated flat plate with the Hall effects. Water conveying alumina (Al2O3), silver (Ag) and titanium oxide (TiO2) nanoparticles experiencing convectively heated as appropriate in the engineering or industry are investigated. The leading equations are non-dimensionalized using relevant similarity variables and then numerically cracked via utilizing the bvp4c solver. The impressions of different pertinent parameters on the axial velocity, transverse velocity and temperature profile along with heat transfer and drag force are discussed carefully. Double solutions are observed in the opposing flow; however, a single solution is obtained for the assisting flow. Also, the results indicate that due to nanofluid, the velocity boundary layer thicknesses decrease and the thermal boundary layer width upsurges. Further, the flow and the characteristics of heat transfer can be controlled using a magnetic field.

Numerical Modeling and Design Challenges of Boundary Layer Ingesting Fans

Abstract Studies show that boundary layer ingesting (BLI) propulsion can provide significant fuel burn reduction relative to pylon-mounted turbofan engines. However, this type of propulsion can lead to serious difficulties and engineering challenges. Numerical analyses of the fan with a uniform flow at the inlet and that exposed to the distorted flow were performed. These required the use of a full-annulus unsteady time-marching computational fluid dynamics (CFD) model, which was validated with experimental data obtained at a test rig. The first negative effect of the distorted inlet velocity profile is a variable incidence angle of the rotor. Both the calculations and the experiment show the nonuniform axial and tangential velocity profiles in front of the rotor. As a result, significant changes in the angle of attack of the blades and corresponding unsteady rotor loads are observed. The research was performed for different operating conditions to obtain performance curves and assess the BLI influence. This demonstrated the second problem arising from the operation of the fan with the distorted flow at the inlet, which is a reduction of the stall margin (48% reduction in the experiment). The whole stage was optimized for the axisymmetric flow to ensure a required value of stall margin and the highest possible efficiency at the design point. The experimental efficiency of the rig at the design point with the distorted inlet was 2.05% lower than the undistorted one. The CFD model shows a 1.25% reduction. Similar reductions were obtained for other operating points.

Peristaltic pumping of hybrid nanofluid between concentric tubes with magnetic device effects: Applications to human endoscopy

The applications of hybrid nanomaterials report excellent thermal performances and convey applications in various processes like energy production, extrusion processes, nuclear reaction, manufacturing and engineering processes, industrial domains, aero-spaces etc. Additionally, the impacts of magnetic devices in advance endoscopy and biological transport phenomena are also a hot topic of research in the current era. This study deals with the physical influences of magnetic device on the peristaltic transport of a viscoplastic nanofluid between the two-dimensional curved concentric tubes. The curved shape structure of flow geometry from the external side with a flexible complex nature of the peristaltic endoscope present inside that is similar to the endoscopy of a living organ. The non-Newtonian Casson liquid polymer is employed for assist the dynamic of viscoplastic materials. The concentration of silver (Ag) and alumina (Al2O3) nanoparticles are utilized in the clay as a base fluid. The governing equations are modeled by using the curvilinear coordinates. The conducting investigation is worked out for creeping pattern and under the high wavelength consideration. The analytical proceedings for flow features, for examples, axial velocity profile, pressure gradient, pressure rise, shearing stress tensor and temperature profile, are obtained by using integration technique. It is noted that the velocity magnitude for viscous fluid is larger in magnitude as compared with the viscoplastic fluid. The magnitude of temperature rate get slower variation for volumetric concentration parameter (range of concentration parameter is 0%–4%). The current model has been used in bio-engineering processes, industrial fluid mechanics, thermal processing, endoscopy of living organs and cooling systems.

On Flame Extinction and Free-Floating Limits Using a Large Diameter Opposed Jet Burner

ABSTRACT This paper presents studies on flame extinction and associated flame structure using a large diameter (40 mm) opposed jet burner for the first time. The extinction experiments were carried out at various nozzle separation distance (L) to diameter (D) ratios (L/Ds) for methane-air non-premixed flames, while all similar experiments in the past literature are with smaller burner diameters (<25 mm). The extinction studies were used to determine the free-floating limits of the burner, and a detailed analysis of the effect of nozzle exit diameter and Applied Stress Rates (ASRs) on the free-floating limits are reported by comparing with similar works in the past. The Particle Image Velocimetry (PIV) technique was used to determine the axial velocity profiles and local extinction strain rates (Kl) of the flames. Based on the experiments, a correlation for the free-floating separation distance from the stagnation plane (zFF) is proposed, which was found to be proportional to the square of the ASRs. The reported free-floating limits in the literature using various diameters agree with the observed data trend. This solves the ambiguity regarding the free-floating limits of opposed jet burners and provides a general trend of the free-floating separation distance (LFF) even in the off-extinction operation regime. 2D axisymmetric simulations were carried out using realistic boundary conditions on the OpenFOAM® platform to predict flame extinction and, consequently, global flame extinction strain rates (Kg). The model predicts the Kg values and also its trend with L/Ds accurately. The model also captures the flame structure before extinction for various L/Ds.

A shape function approach for predicting deteriorated heat transfer to supercritical pressure fluids on account of a thermal entry length phenomenon

The paper addresses the problem of predicting deteriorated heat transfer to supercritical pressure fluids, trying a novel approach whose main features are obtained by consideration of the experimental trends of a meaningful series of experimental data. This approach takes into consideration the modifications that the axial velocity profile undergoes at the entrance of a bare tube, when a supercritical pressure fluid is heated at the wall and decreases its density owing to thermal expansion, giving rise to buoyancy effects. Combining the observation of measured wall temperature trends with their successful predictions by CFD RANS models, the effects giving rise to flow laminarization are firstly interpreted as a very peculiar form of the entry length problem applicable to supercritical pressure fluids. Then, their quantitative prediction is addressed by the use of an iterative procedure based on shape functions tailored on the observed trends of the Nusselt number and of the consequent wall temperature trends. In this frame, the results of a recently developed fluid-to-fluid similarity theory for heat transfer at supercritical pressures provide indication about the relevant dimensionless numbers to be involved in determining the shape functions. Being based at the moment on a series of water experimental data collected at 25 MPa for vertical upward flow, the methodology may suggest a way for predicting heat transfer deterioration in the proposed supercritical water nuclear reactor conditions, providing an additional means to tackle this critical problem by a different approach that may result useful as a practical means to bound expected wall temperature trends.